Електротехнички факултет [Конференције] / Faculty of Electrical Engineering [Conference paper]

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https://vaseljena.ues.rs.ba/handle/123456789/821

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Analysis of single-phase PLL with novel two-phase generator for gridconnected converters
(2011) Lale, Srdjan; Lubura, Slobodan; Šoja, Milomir; Ikić. Marko
It is very important for proper work of gridconnected converters to have accurate detection of phase angle, frequency and amplitude of grid voltage. Estimation of these grid parameters can be achieved using PLL (phase locked loop) based on SRF (synchronous reference frame) theory. This PLL should have robustness against noise and offset introduced by measurement and data conversion. This paper proposes an improved PLL alorithm that has excellent noise and offset rejection property. The main part of the proposed PLL is a novel two-phase generator which is used to obtain two quadrature signals for SRF block and PI regulator in closed control loop.
Implementation of CORDIC Algorithm on FPGA Altera Cyclone
(2012) Ristović, Milica; Lubura, Slobodan; Jokić, Dejan
In paper is presented HDL Code generation of Cordic Algorithm in MATLAB/Simulink, using HDL Code generation tool, and its implementation on FPGA Altera Cyclone, using Altera Quartus II. There are also tested data types which Cordic uses, as well as time which is need for sine or cosine calculation of given angle, depending on these data types. With this information Cordic can be easily implemented in any digital system.
Experimental verification of single-phase PLL with novel two-phase generator for gridconnected converters
(2012) Lubura, Slobodan; Šoja, Milomir; Lale, Srđan; Ikić. Marko
For proper work of grid-connected converters it is important to have accurate detection of phase angle, frequency and amplitude of grid voltage. Estimation of these grid parameters can be achieved using PLL (phase locked loop) based on SRF (synchronous reference frame) theory. This PLL should have robustness against noise and offset introduced by measurement and data conversion. This paper proposes an improved PLL algorithm that has excellent noise and offset rejection property. The main part of proposed PLL is a novel two-phase generator which is used to obtain two quadrature signals for SRF block and PI regulator in closed control loop. Performances of proposed PLL are verified through experimental results given in this paper.
Prediction and measurement of electromagnetic radiation at Krajina Square in the city of Banja Luka
(2013) Medjedovic, Petar S.; Suka, Darko S.
This work is only a small part of the research carried out in the project: "Prediction, measurement and analysis of composite electromagnetic (EM) field of artificial radiation sources", funded by the Ministry of Science and Technology of the Republic of Srpska. The main objective of the project is to locate the representative measuring points for future monitoring network for continuous measurements and recordings of maximum levels of EM non-ionizing radiation, in the spreading center of Banja Luka area of about 10km². Regarding that, previously was conducted verification with a software package used for a smaller area, by comparing the predicted and measured values of electromagnetic fields strength. For this purpose the pedestrian zones were treated, which are the surfaces and routes with the largest population flow. This paper gives a brief description of the research of EM radiation levels on the surface of 0.008km² in the frequency range from 50MHz to 3GHz.
A Graphical Editor for RESTful Sensor Web Networks Modeling
(2014) Vujović, Vladimir; Maksimović, Mirjana; Perišić, Branko; Milošević, Vladimir
Effectiveness of communication is measured by speed, ease, and accuracy in which the information can be understood. From the cognitive aspect graphical presentations are usually more effective than textual ones, especially when communication between end-users and/or domain practitioners is concerned. Model-Driven Engineering (MDE) graphical tools have become extremely popular concerning the development of applications for a large number of domains. In this paper the emphasis is put on the design and implementation of Graphical Editor for RESTful Sensor Web Network in order to equip designers, with no expert knowledge in specific solution-domain, with a tool that would enable them to easily define tasks, specify network architecture and implement RESTful services. Based on the pilot sensor network design model, the verification, validation and proper functionality of proposed Graphical Editor are performed.
Evaluating the optimal heat detector deployment for fire detection
(2014) Maksimović, Mirjana; Vujović, Vladimir; Perišić, Branko; Milošević, Vladimir
Wireless Sensor Networks (WSNs), composed of spatially distributed autonomous sensor nodes, have a wide range of application. One of the most interesting phenomena that can be monitored by WSN, among various physical, chemical and biological phenomena and different kind of events, is fire. In case of fire presence continuous monitoring and/or recording of sensitive or restricted parts are necessary for timely response and reaction. Fire monitoring applications require accurate deployment of the sensor nodes because their positions have a dramatic impact on the effectiveness of the WSN and the efficiency of its operation. The choice of the deployment scheme depends highly on the type of sensors, application and the environment that the sensors will operate in (residential buildings, hospitals, historical buildings, malls etc.). The main advantage of WSN usage can be also identified as a simple reconfiguration and maintenance of the created infrastructure, what can be of great importance for systems that are physically unaffected by changes, but they tend to change in terms of safety (e.g. ships, oil productive platforms, etc.). Knowing that the positions of nodes have a dramatic impact on the effectiveness of the WSN and the efficiency of its operation, in this paper the various strategies for positioning nodes in WSNs are considered: grid, triangular and strip. The objective of this paper is to properly place the heat detectors in certain indoor area, in such way that next two important network design objectives are satisfied: to maximize the network lifetime after fire ignition and to use a minimum number of sensors in order to achieve full area coverage.
MasterBroker: REST oriented Service Broker
(2014) Kosmajac, Dijana; Vujović, Vladimir; Maksimović, Mirjana; Davidović, Nikola; Perišić, Branko
Considering historical development and expansion of World Wide Web, it is obvious that there is no unique tendency in terms of supporting software technologies. Moreover, vast amount of different technologies has emerged because the system as a whole became quite complex and diverse. Heterogeneity, which is characteristic of distributed systems based on Web, is one of the main challenges which system designer may encounter. The paper presents and discusses a software solution proposal which mainly relies on widely deployed Internet stack protocols and REST (Representational State Transfer) style of Web services. Further, the paper compares standardized approach based on SOAP (Simple Object Access Protocol) to a proposed one based on REST. As a result, the implementation represents a control component with broker architecture
A Custom Internet of Things Healthcare System
(2015) Vujović, Vladimir; Maksimović, Mirjana; Perišić, Branko
Health is the fundamental capability humans require to perceive, feel, and act effectively, and as such, it represents a primary element in the development of the individual, but also of the environment humans belongs to. That is why it is necessary to provide adequate ways and means to ensure the appropriate healthcare delivery based on parameters monitoring and direct providing of the medical assistance. The new technologies development and implementation, especially the Internet and Wireless Sensor Networks (WSNs) commonly known as the Internet of Things (IoT), enable global approach to the health care system infrastructure development. This leads to e-health system that, in real time manner, supplies a valuable set of information relevant to all of the stakeholders (patients, medical and paramedical stuff, and health insurance) regardless their current location. Commercial systems in this area usually do not meet the general patient needs, and those that do are usually economically unacceptable due to the high operational and development costs. In this paper, based on well-known low-cost technologies, there is a Do-It-Yourself (DIY) solution for a sustainable and adaptable patient oriented infrastructure development, presented.
Aspects of remote monitoring and recording system of non-ionizing electromagnetic radiation
(2015) Šuka, D. S.; Simić, M. I.; Pejović, P. V.
The paper discusses the possibilities and aspects of continuous, remote monitoring system of non-ionizing electromagnetic radiation using certain networks for measuring and storage of measurement results. First are stated the motives for the usage and installation of such networks and preliminary activities necessary for the proper design of systems, as well. Further, the system architecture and methodology of such measurements are described, where defined requirements are placed in front of the remote monitoring station. Control of measurements is achieved from a remote distance via GSM, GPRS or other telecommunication services. Such systems allow full control of remote monitoring stations, as well as continuous recording of all measurement results. Measurement results from all monitoring stations are collected in control centre, where a comprehensive analysis of all measurement data can be done and published on certain website afterwards.
A Proposition of Low Cost Sensor Web Implementation Based on GSM/GPRS Services
(2015) Vujović, Vladimir; Maksimović, Mirjana; Perišić, Branko; Milošević, Goran
In past few years, automatic remote systems for monitoring a wide range of environment or process parameters have exposed a rapid growth concerning the technology issues. Entering the era of Internet of Things (IoTs), a highly dynamic and radically distributed networked system, usage of small, cheap, flexible and end-user programmable computer hardware becomes apparent. These objects, deployed in various environments, are able to communicate and to interact among themselves, with end-users or other entities in the network. Using such objects, tasks like monitoring, control or data processing can be easily done. But, in some case, the target environments are often too dangerous, hazardous, unwired, or difficult to access. In such unfriendly environments there are many challenges for monitoring systems (wireless sensor networks) deployment and maintenance. As the possible solution, in this paper we have suggested the creation of an economical remote monitoring system, based on cheap computer board (Raspberry Pi), wireless sensors and GSM/GPRS (Global System for Mobile Communications/General packet radio service). In other words, the Raspberry Pi platform is utilized as central processing unit which provides a set of services for accessing sensor data, and communicates with end users, while different types of sensors (depending of target parameters) can constitute the detection module. 3G/4G USB Modem or GSM/GPRS shields can be used as GSM/GPRS communication module in order to ensure Internet connection. A whole system presents an IoT solution, precisely a Sensor Web node, which can be accessed all over the world, and provide information from a monitored environment. Performed research shows a possibility of setting up this system for a remote communication, control function and monitoring in unfriendly environments. The usage of low cost pieces of hardware verifies that the Raspberry Pi is highly suitable for numerous IoT concept applications and especially in the unfriendly environments.
Adaptive Delay Bank Filter for Selective Elimination of harmonics in SRF-PLL structures
(2015) Lubura, Slobodan; Šoja, Milomir; Lale, Srđan; Ristović, Milica; Ikić. Marko
This paper proposes the usage of adaptive delay bank (ADB) based on cascaded delayed signal cancellation (CDSC) structure for selective elimination of the harmonics in the synchronous reference frame phase locked loop (SRF-PLL) structures. The ADB is inserted inside the SRF-PLL structure and it is frequency adaptive, which is the advantage over CDSC structures which are used in PLL as pre-filters, not being adaptive at all. Detailed mathematical analysis and simulation results confirmed suggested method for selective harmonic elimination in PLL.
Resource: A connection between Internet of Things and Resource-Oriented Architecture
(VDE VERLAG GMBH · Berlin · Offenbach, Germany, 2015) Vujović, Vladimir; Maksimović, Mirjana; Kosmajac, Dijana; Perišić, Branko
The Internet of Things (IoT) appears like a new paradigm in the globalization process. The term "Things" refers to the interconnected smart elements of any kind and purpose that can be located anywhere and interact with each other according to the predefined protocol. Because of the unlimited variety of different structures and behavior, it is essential to find the way to uniformly represent and implement the IoT in the real world environment. Referring the good practice of distributed Internet systems, like service oriented architecture (SOA), an implementation of IoT as a resource, that appears like the “black box” from the users’ point of view, looks promising. The analysis of service oriented architecture and IoT, and subsequently, the selection between SOAP (Simple Object Access Protocol) and REST (Representational State Transfer) implementation style are presented in this paper. Because the main building element of REST services is a resource, REST appears as a “natural” choice for IoT description. Thus, the usage of REST services for describing IoT, and adequate system and its implementation, based on this idea, are presented in this paper too.
A Low Cost Internet of Things Solution for Traceability and Monitoring Food Safety During Transportation
(2015) Maksimović, Mirjana; Vujović, Vladimir; Omanović-Mikličanin, Enisa
In the last decade, we are faced with a dozen food crisis, which have impact on human health. EU as response to food contamination applies a set of laws and standards for food traceability through all stages of production, processing and distribution, forcing that all food and feed operators implement special traceability systems. One of the main and a crucial element of this system is food transport from manufacturer to consumer, and possibility for monitoring food quality through the transportation process. Applying new technologies, like Internet of Things (IoT), nowadays it is possible to connect food producers, transportation and hospitality/retail companies. A low cost solution based on IoT for real-time food tracebility and monitoring in food transportation process is presented in this paper.
Analysis of discretization methods applied on DCSOGI block as part of SRF-PLL structure
(2016) Ristović Krstić, Milica; Lubura, Slobodan; Lale, Srđan; Šoja, Milomir; Ikić. Marko; Milovanović, Dragiša
Phase Locked Loop (PLL) is wide used for grid parameters estimation, as well for grid-converters synchronization. Key block at single-phase Synchronous Reference Frame PLL (SRF-PLL) structure is two-phase generator which is used for generation of two quadrature signals, which are necessary for SRF block. One of the issues that could appear during estimation of grid parameters is appearance of DC offset in measured grid voltage. In this paper is described second order generalized integrator (SOGI) which is capable to fully reject DC offset and noise which could appear in measured input grid voltage. This two-phase generator is named DC-SOGI. Analog DC-SOGI is made of two second order filters. While these structures are mostly digitally implemented, then it is interesting to analyze discretization method and sampling time impact on two-phase generator. Simulation results confirm given assumption.
Novel Band-Pass and Notch filter with Dynamic Damping of Fractional Order
(2017) Bošković, Marko; Šekara, Tomislav B.; Rapaić, Milan R.; Lutovac, Budimir; Daković, Miloš; Govedarica, Vidan
The paper introduces a novel the second order band-pass and notch filter with dynamic damping factor βd of fractional order. Indeed, the factor βd has a form of fractional differentiator of order α, i.e. βd=β/s α, where β and α are adjustable parameters. Shaping of the frequency response enables achieving better phase response compared to the integer-order counterparts which is of great concern in many applications. The aim of the paper is to exploit an extra degree of freedoms of presented filters to achieve the desired filter specifications and obtain desired response in the frequency and the time domain.
Improving computing issues in Internet of Things driven e-health systems
(2017) Maksimović, Mirjana
The Internet of Things (IoT) progress shows a positive influence on all aspects of healthcare. Enabling access to high-quality healthcare to anyone, from anywhere are the main advantages of the IoT-driven e-health systems. Increasing numbers of medical devices and sensors and 24/7 monitoring of health parameters, consequently lead to enormous quantities and varieties of data. Having in mind the amounts of generated data and importance of on-time diagnosis and decision making as well as a significance of fast reactions in a case of detected abnormalities, transmitting all data to the Cloud for analysis may not be appropriate. For that reason, implementing a Fog computing, which realizes mini analytic processing centers at the edge of the network, appears as a better approach. This paper analyzes the manners and benefits of implementing Fog computing in the IoT-driven e-health systems. It is expected that the IoT and Fog computing together will revolutionize healthcare like nothing else before.
Preservation of Cultural Heritage Sites using IoT
(Faculty of Electrical Engineering, University of East Sarajevo, 2019) Maksimović, Mirjana; Ćosović, Marijana
Religious/historical buildings ought to be preserved for as long as possible. The ancient structures themselves and the rich collections they store represent irreplaceable wealth for future generations. They also provide the space for the customs and traditions to sustain. In addition, cultural heritage sites can stimulate economic growth but need to be maintained as well. This paper proposes an effective and affordable solution for the monitoring of preservation conditions of the Church belonging to Eastern Orthodox cultural heritage. The solution is based on utilization of modern Information and Communication Technologies (ICT) and services with general structure and main design principles using the three-layer IoT architecture. This research is an ongoing work only involving the first step towards realization of preservation monitoring system.
Time Series Prediction of Air Pollutants
(Faculty of Electrical Engineering, University of East Sarajevo, 2019) Janković, Radmila; Ćosović, Marijana; Amelio, Alessia
Pollution levels are highly dependent on the meteorological parameters, as the weather conditions dictate pollution dispersion and concentration. With the rise of global environmental protection initiatives, there is also a need for accurate prediction of pollution levels. This paper presents a time series prediction of NO2 and CO given four meteorological parameters: (i) air pressure, (ii) relative humidity, (iii) average daily temperature, and (iv) wind speed, using a Nonlinear Autoregressive Exogenous (NARX) neural network. The research is a case study of three European countries: (i) Serbia, (ii) Bosnia and Herzegovina, and (iii) Italy, and involves data from 2014 to 2016 for a total of 1096 instances. The results show that the best prediction accuracy is obtained for CO for data regarding Italy and Bosnia and Herzegovina, and for NO2 for data regarding Serbia. Moreover, the best predictor variables of NO2 are air pressure and relative humidity, followed by the wind speed. The best predictor variables of CO are pressure and temperature for Bosnia and Italy, and wind speed for Serbia
Classication Methods in Cultural Heritage
(Research Area of the CNR of Pisa Institute of Information Science and Technologies “A. Faedo” (ISTI), 2019) Ćosović, Marijana; Amelio, Alessia; Junuz, Emina
This paper describes relevant classifi cation methods applied to the cultural heritage context. In particular, a categorisation of the classifi cation methods is provided according to tangible and intangible cultural heritage, where movable and immovable objects can be in the focus. A short description of each method is reported for each cultural heritage category in terms of feature representation, classifi cation approach and obtained results. The proposed survey can be useful in the research community of pattern recognition and visual computing for exploring the current literature about the topic. It will hopefully provide new insights for the advancement of knowledge discovery in cultural heritage.
An Improved Version of Student Attendance Management System Based on RFID
(Faculty of Electrical Engineering, University of East Sarajevo, 2019) Mijić, Danijel; Bjelica, Ognjen; Durutović, Jelena; Ljubojević, Miloš
Student attendance registration is one of the routine but time-consuming tasks of teaching staff at higher education institutions. Various technical solutions are implemented to alleviate the administrative burden and partly automate this task. Most of them include the use of one or more of the following - Radio Frequency Identification (RFID) technology, biometric solutions such as fingerprint and face recognition and mobile devices - mostly smartphones. In this paper, we present an improved version of our system based on RFID and some results of its use in a real environment. The main improvements have been made to a hardware component RFID reader and to a web-based application that is used by the faculty staff. Besides the usual features of similar systems related to student attendance, the system also includes features that enable integration with external systems, recording of necessary data regarding the work of teachers in class and generating of periodical reports on their work.

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